Well the title says it all.

Should I get 4.10 or 3.73 ring & pinions installed in my 05 GT automatic ?

The 05 GT automatic comes stock with 3.31 gears (manual is 3.55?).

Some people say that 4.10 is too much for the 05 GT automatic.

I can also get 3.90 (non Ford) gears - Ford does not appear to make 3.90 gears (for Mustangs). I don't trust non Ford gears.

I'm really interested in hearing from people who have installed gears in their automatic 05s.

 

3.73 Ford Racing Performance Parts with an automatic. I paid $168.95 for my FRPP gear set. Don't recommend Non-Ford gears.

 

ok, so Motive has a 3.90 ratio?..I have been deciding between the 3.90 an 4.10 for my manual..Not to hijack the thread, but maybe somebody could give me some insight and recommendation. I drive on the hwy 40 mi each way to work and would like to keep somewhat in the same mileage range that the car provides now..Do you think the 3.90's would be a better choice in terms of mileage or would it not even be noticeable over the 4.10's?

 

I was adviced by a mechanic to ONLY get genuine Ford ring & pinions (for Mustangs).

 

Im going with 3.73 in the very near future. This will be my first mod besides my K&N filter, 3.90 is not a bad choice but I want ford parts.

 

4.10s are way more gear than you need with an automatic.

Everyone seems to forget that the '05 GT has a 5 speed automatic with a very tall 1st gear, 3.23 vs the 2.84 1st gear in the old 4 speed auto.

Also the OD ratio for the automatic is .71 vs .62 for the manual.

I strongly recommend that you go with 3.90 or 3.73 gears.
3.90s in an 05 auto will act like 4.20 gears in a 04 auto.
3.73s in an 05 auto will act like 4.00 gears in a 04 auto.
And that's not even including the effect of the extra HP and torque that the 05 has over the 04.

 

Get the 4.10s. 3.31 to 3.73 is not enough change to spend the money on.

Trust me, you will LOVE the 4.10s.

 

See below, double post.

 

Not forgetting that at all...4.30s and an auto is a very good combo in the 99-04 cars.

 

4.10's have been perfect for me. I get 22 mpg at 80 mph cruising for over 75 miles. They pull hard and get lots of pwoer to the ground. Anything higher (3.90, 3.73) you will kick yourself.

I cant speak on 4.30 gears. I will say I had 4.56 gears at one time in a 65 mustang - it was way too much for the 3 speed auto.

-Bryan

 

So you think getting 3.73 gears for an automatic 05 GT would be a mistake?

At 70 mph, what does your RPM read?

I already have an SCT Excalibrator (I think we've bumped into each other on SCT forums ).

SCT's ExtremeTune software allows us to change axle settings but I heard sombody mention that you have to also change shift points for automatics. That doesn't make sense to me because the automatic shifting has nothing to do with axle ratios.

 

if you dont do highway driving get 4.30's if you do drive on the highway id go with 4.10's or 3.73's if you are a wuss lol

 

Wondering if any of you guys can help me out. I have a 92 LX and got the optional 2.73 ratio as I don't care so much for low end acceleration but was more interested in low rpm at cruise. (It's about 1800 rpm at 65mpg, 16" wheels) My 92 has 200k on it now and the engine has been flawless. Does operating at the lower rpm at cruise, in the long run, affect engine life? and is that why the 302 has run so well?

I am interested in 05 but only 3.55 is offered. Would anyone know how much rpm I'm giving up at 65? I understand the 17" wheels would help a bit? Is it possible to get lower ratio from Ford? I do 450 mile cruises often to my home town and would think running at the higher ratio would be detrimental to the engine over the long run, not to mention fuel economy. Is this true?

Any comments on this would help my decision..